Device for driving the hands of monumental clocks



I June 9, 1925.

A. MAYER DEVICE FOR DRIVING THE HANDS OF MONUMENTAL CLOCKS Filed Dec.'15, 1922 .Patented June 9, 1925.

UNITED STATES PATENT OFFICE- .ABMAND MAYER, or LnvALLoIs-rnnnn'r, rnancnnnvxon FOR DRIVING 'rnn Harms or MONUMENTAL cnocxs.

Application filed December 16, 1922. Serial No. 607,403.

To all whom it may concern: I

Be it known that I, ARMAND MAYER, a citizen of the French Re ublic,residing at Levallois-Perret, France, ave invented cer tain new anduseful Improvements in Devices for Driving the Hands of MonumentalClocks (for which I have filed an applica; tion for patent in France onthe 17th December 1921), of which the following is a specification. I

Turret clocks have become known comprising auxiliary movements andcontact devices, which when the electric current fails,

effects automatically the readjusting of the hand mechanism. In thearrangements of known type contacts-are used which rotate with the handswhich is however undesirable, as, when the working current fails, thecontact givingI fails also.

This invention as for its object to avoid this inconvenience.

The invention consists in connecting with one another the hands of theturret clock and the auxiliary movement by means of a differential geardesigned to close the circuit of a motor, which drives the hands of theturret clock, as soon as there is no longer synchronism between theauxiliary movement and the hands of the turret clock.

In order to make the invention fully understood I shall hereafter(proceed to describe the same with reference to the form of constructionshown by way of example on the accompanying drawing, wherein:

Fig. 1 shows in section the arrangement according to the invention.

Fig. 2 is a plan view of Fig. 1.

The auxiliar movement .1 and the axle 2 of the dial tram drive each abevel wheel 3 and 4 of a differential gear Fig. 2) the planet wheels '6and -7 of w ich revolve around the shaft 8-.fixed in the supportingframe 9 of the planet wheel rotatably mounted on axle 2.

A gear wheel 10 rigidly fixed on the supportin frame 9 drives a spurwheel 12 throug the intermediary of a toothed wheel transmission 11. Theratio of. transmision of this .gear is selected so that the supportingframe 9 of the planet wheels executes six revolutions when the spurwheel 12 coinpletes one revolution.

On the sup orting frame 9 of the planet wheels a note ed disk 13 and onthe spur wheel 12 a notched disk It is arranged. Rollers 15 and 16bearagainst the periphcries of said notched disks 13, 14, respectively.These rollers 15, 16 are mounted on arms 17, 18 fixed at the ends of thehollow shaft 19. On this hollow shaft 19 a lever 20 is further fixedinto theend of which a screw 21 is screwed adapted to come in touch witha counterscrew 22 when one of the rollers 15, 16 is being raised.

The circuit 24 is closed across the motor 23 as soon as the contactbetween the screws 21 and 22 is closed. This hand train is driven fromthe motor 23 for instance by means of a worm 25 and worm wheel 26. Theremaining part of the mechanism is not illustrated as it is generallyknown. The motor 23 ma evidently serve for normally driving the and of aturret clock.

' The operation of the mechanism is as follows At the normal working thetwo bevel wheels 3 and4 revolve synchronously but in inverse directions.Thesupporting frame 9 of the planet wheels remains stationary and as therollers 15, 16 are in engagement with the notches of disks 13, 14 thecontact at 21, 22 is interrupted so that the mecha-' nism cannotoperate. rent in the circuit fails, the hands of the turret clock willstop, thehands of the auxiliary movement continuin to rotate. As thebevel wheel 4 is steppe but wheel 3 continues to rotate the supportingframe 9 or the plant wheels must rotate at a s eed which is equal tohalf the speed at w ich the wheel 3 revolves. The supporting frame 9will therefore execute one rotation in two hours. Owing to thetransmission gear 10, 11, 12 the second disk 14 revolves also butexecutes one revolution in 12 hours.

Herefrom results that, as soon as a sumciently great angular difierenceexists between the two pairs of hands, the roller 15, which isdisengaged from the notch of disk 13, permanentl closes the circuit ofthe motor on the main line so that as soon as the current be us to flowagain through the main line t e motor is started and the hands of theturret clock rotate rapidly. At the same time the bevel'wheel 4 of thedifferen- As soon as the curtial gear rotates the supporting frame 9 of14, e. g. whenthe hands of the turret clock synchronize with those ofthe auxiliary movement. As two disks (13 and 14) are provided thesynchronization is ensured for the hour hand as well as for the minutehand.

The same will be the case if the angular difference between the hands ofthe turret clock and those of the auxiliary movement increases beyond apredetermined value either owing to an accidental failing of thecurrent, caused for instance by snow, or owing to the failing of thenormal movement.

I claim i 1. A driving mechanism for the hands of turret clockscomprising in combination with the hand mechanism, an electro-motor ingear with said hand mechanism, an auxiliary clockwork movement, adifferential gear connectin said han driving mechanism, a reducing gearfor recording the revolutions of the central element of saiddifferential gear, a source of electric current connected with saidelectro-motor, and a set of contacts controlled by said central elementof said differential gear closing the circuit of the motor with saidsource of current and interrupting said circuit only when theindications of the turret clock and of the auxilsaid auxiliary movementwith iary nism.

2. A driving mechanism for the hands of turret clocks comprising incombination with the hand mechanism, a motor for driving said mechanism,an auxiliary mechanism, justing the hand mechanism when the curretfalls, a differential gear connecting said auxiliary movement and saidhand mechanism, two notched disks one for the hour hand and the otherfor the minute hand connected with the differential gear, rollersbearing against the rims of said notched disks, levers carrying saidrollers and designed to act upon the contacts of said contact mechanismin such a manner that the circuit for said motor drivin the hands is outonly when the hands of t e turret clock and those of the auxiliarvmovement are in synchronism.

In testimon whereof I afiix my signature in presence 0 two witnesses.

ARMAND MAYER.

clockwork movement are in synchro- Witnesses BERTHOLD MONANDY, Gnn'rmuonBACHMANN.

a contact device for automatically ad-

